For the purpose of obtaining maximum rat- stoppage at a minimum cost to the owner or occupant of business buildings, the following regulations are set forth as the minimum requirements for applying rat- stoppage to business buildings:
(a) Approval of materials and method. The director shall approve all materials used and the method of installation.
(b) Specifications for metal. Solid sheet metal, expanded metal, and wire cloth specified in these regulations must have a rust-resisting, protective coating, preferably galvanized.
(c) Coverings for foundation wall ventilator openings. All foundation wall ventilator openings must be covered for their entire height and width with perforated sheet metal plates of a thickness not less than 14 gauge, or with expanded sheet metal of a thickness not less than 18 gauge, or with cast iron grilles or grates, or with any other material of sufficient strength and equal rat-resisting properties. The openings in the metal must be small enough to prevent the ingress of rats, and in no instance larger than one- half inch.
(d) Miscellaneous foundation and exterior wall openings. All foundations and exterior wall openings, excluding those used for the purpose of ventilation, light, doors, and windows, such as those openings around pipes, electric cables, conduits, openings due to deteriorated wall, masonry or concrete, shall be protected against the ingress of rats by closing such openings with cement mortar, concrete or masonry, or close-fitting sheet metal or suitable size pipe flanges or other material with equal rat-resisting properties, which shall be securely fastened in place.
(e) Doors.
(1) All exposed edges of the lower eight inches of wooden doors and door jambs, serving as front, rear, or side entrances into business buildings, from the ground, basement or cellar floors, and other doors accessible to rats, must be protected against the gnawing of rats by covering such door and jambs with solid sheet metal of not less than 24 gauge thickness. The same material must be used on door sills or thresholds, or such door sills or thresholds may be constructed of cement, stone, steel, or cast iron.
(2) All doors on which metal flashing has been applied must be properly hinged to provide for free swinging. When closed, doors must fit snugly so that the maximum clearance between any door, door jambs, and sill is not greater than three-eighths of an inch.
(3) Doors, door jambs, and sills of coal chutes and hatchways that are constructed of wood must be covered with solid sheet metal of 24 gauge or heavier, or they may be replaced with metal chutes of 24 gauge or heavier installed in such a manner as will prevent the ingress of rats.
(4) Door jambs and sills constructed of metal, concrete, masonry, stone, or cement mortar, or cast iron and steel, when fitting closely to exclude rats, are not required to comply with this subsection.
(f) Windows.
(1) All windows and other openings for the purpose of light or ventilation, located in the side or rear of exterior walls and within 30 inches above the existing ground level immediately below such opening, must be covered for their entire height and width, including frame, with wire cloth of 19 gauge or heavier, having a mesh of not larger than one-half inch.
(2) All window and other openings for the purpose of light or ventilation in the exterior walls that may be accessible to rats by way of exposed pipes, wires, conduits, and other appurtenances must be covered with guards of wire cloth of 19 gauge or heavier, having a mesh of not larger than one-half inch, or, in lieu of wire cloth covering, the pipes, wires, conduits, and other appurtenances must be blocked from rat usage by installing sheet metal guards of 24 gauge or heavier. Such guards when used on horizontal pipes, wires, conduits, or other appurtenances must be placed in a vertical position [and] be snugly fitted around the pipe, wire, conduit, or other appurtenance.
(3) Such guard must measure not less than 12 inches beyond and on all sides of the pipe, wire, conduit, or other appurtenance where the intervening space between the wall and pipe permits, and must extend 30 inches in an upward direction and 12 inches in a downward direction, and must be securely fastened to the pipe, wire, conduit, or other appurtenance and also the adjacent wall wherever practicable so that the guard will remain in a vertical position at all times.
(4) Such guards when used on vertical pipes, wires, conduits, or other appurtenances must be fitted snugly around the pipe, wire, conduit, or other appurtenance, must be placed in a horizontal position (right angle to pipe, etc.), and must extend horizontally from the pipe, wire, conduit, or other appurtenance for a minimum distance of 12 inches beyond and on all sides of the pipe, wire, conduit, or other appurtenance, where the intervening space between pipe and wall permits, and must be securely fastened to the pipe, wire, conduit, or other appurtenance and also to the adjacent wall wherever practicable in such manner that the guard will remain in a horizontal position at all times.
(g) Light wells in sidewalks.
(1) Light wells with windows in exterior walls that are located below the outside ground level must be protected from the ingress of rats by one of the following methods:
(A) Installing over light wells cast iron or steel grills or steel gratings, or other material of equal strength and rat-resisting properties, with openings in grills or gratings not to exceed one-half inch in shortest dimension.
(B) Installing securely to and completely covering existing metal grills that are broken or have openings larger than one-half inch in shortest dimension, or otherwise defective, with expanded metal of 18 gauge or heavier, having openings not greater than one-half inch in shortest dimension, or with 16 gauge or heavier wire cloth with one-half inch mesh.
(2) At the option of the owner, the opening in the wall of the building below the grate may be entirely closed with brick or concrete, or partially closed and the remaining open space covered with 19 gauge or heavier wire cloth with mesh not to exceed one-half inch.
(h) Wood frame exterior wall construction.
(1) Business buildings constructed on piers must have the intervening space between floor level and ground protected against the ingress of rats by installing a solid masonry or concrete curtain wall not less than four inches thick around the entire perimeter of the business building and extending such curtain wall to a depth of not less than 30 inches below the surface of the ground level with a 12 inch wide, four inch deep horizontal flange of the same material at the bottom of such concrete wall, or a solid sheet metal curtain wall of 24 gauge or heavier may be used around the intervening space between floor level and ground level and tying securely into the concrete chain wall at ground level. Properly protected ventilators must be installed in chain wall.
(2) In lieu of the installation of curtain walls, all ground floors of wood construction may be replaced with concrete of not less than three inches in thickness with the exterior walls protected for a height of 12 inches above the concrete floor with masonry, concrete, or solid sheet metal of 24 gauge or heavier. Exterior wall protection must be securely tied into the concrete floor at all points. (Ord. Nos. 7847; 27697)